621.    COMPAGNIE GÉNÉRALE CONSTRUCTION FOURS.  [Experimental Station for Production of Town Gas and of Synthesis Gas From Lignites of Faveau Basin.]  Cahier 81; Fuel Abs., vol. 5, abs. 4703, 1949.

      This plant at Digoin consists of 1 full-scale unit of Woodall-Duckham continuous vertical retorts.  The lignite contains 8.5-9% moisture, 14.4% ash, 46% volatiles, and 54% fixed C on the dry ash-free basis.  When making synthesis gas the central-gas offtake was used.  The production of town gas was 350 m.³/long ton or 12,560 cu. ft./ton at 4,000 calories or 420 B.t.u./cu. ft.  The production of Syngaz was 1,030 m.³ or 36,950 cu. ft./ton at 2,900 calories or 300 B.t.u./cu. ft.  The Syngaz was required to have a ratio CO:H₂=2:1 and as little CH₄ as possible.  The composition of town gas was:  CO, 25.7%; H₂, 39.4%; and CH₄, 16.3%.  The composition of Syngaz was:  CO, 27.0%; H₂, 54.2%; and CH₄, 3.2%.  The satisfactory result is attributed to the central offtake giving maximum cracking of CH₄ and an increase in steaming from 8 to 32%.